Crystalline galliosilicate with the erionite-type structure

ABSTRACT

A crystalline, galliosilicate molecular sieve having the erionite-type structure and the following composition expressed in terms of oxide mole ratios in the anhydrous state: 
     
         Ga.sub.2 O.sub.3 :xSiO.sub.2 :yM.sub.2 O:zN.sub.2 O:tQ .sub.2 O 
    
     where M is an alkali metal, preferably sodium, N is an alkali metal other than M, preferably potassium, Q is a cation derived from the templating agent used in synthesizing the galliosilicate molecualr sieve, preferably a choline cation, x equals 5.5 to 30, y equals 0.1 to 0.9, z equals 0.1 to 0.9, t equals 0.1 to 0.6 and y+z+t equals about 1.0. The crystalline, galliosilicate molecular sieve of the invention may be employed, after reducing its alkali metal content, as a component of a catalyst which can be used in a variety of chemical conversion processes, preferably hydrocarbon conversion processes, and most preferably hydrodewaxing, hydrocracking and isomerization processes.

BACKGROUND OF THE INVENTION

This invention relates to crystalline galliosilicates and isparticularly concerned with a crystalline galliosilicate molecular sievehaving the erionite-type structure, methods of producing such amolecular sieve, catalysts containing such a molecular sieve andprocesses for using catalysts containing such a molecular sieve.

Zeolites are well known natural and synthetic molecular sieves that canbe defined as crystalline, three-dimensional aluminosilicates consistingessentially of alumina and silica tetrahedra which interlock to formdiscrete polyhedra. The polyhedra are interconnected to form a frameworkwhich encloses cavities or voids interconnected by channels or pores.The size of the cavities and pores will vary depending on the frameworkstructure of the particular zeolite. Normally, the cavities are largeenough to accommodate water molecules and large cations which haveconsiderable freedom of movement, thereby permitting sorption,reversible dehydration and ion exchange. The dimensions of the cavitiesand pores in a zeolite are limited to a small number of values and canvary from structure to structure. Thus, a particular zeolite is capableof sorbing molecules of certain dimensions while rejecting those ofdimensions larger than the pore size associated with the zeolitestructure. Because of this property zeolites are commonly used asmolecular sieves.

In addition to their molecular sieving properties, zeolites show apronounced selectivity toward polar molecules and molecules with highquadrupole moments. This is due to the ionic nature of the crystalswhich gives rise to a high nonuniform electric field within themicropores of the zeolite. Molecules which can interact energeticallywith this field, such as polar or quadrupolar molecules, are thereforesorbed more strongly than nonpolar molecules. This selectivity towardpolar molecules is the unique property of zeolites which allows them tobe used as drying agents and selective sorbents.

The pore size of a zeolite can vary from about 2.6 Angstroms foranalcime to about 10.0 Angstroms for zeolite omega. The term "pore size"as used herein refers to the diameter of the largest molecule that canbe sorbed by the particular zeolite or other molecular sieve inquestion. The measurement of such diameters and pore sizes is discussedmore fully in Chapter 8 of the book entitled "Zeolite Molecular Sieves,"written by D. W. Breck and published by John Wiley & Sons in 1974, thedisclosure of which book is hereby incorporated by reference in itsentirety. The pore size range of 2.6 to 10.0 Angstroms is particularlysuited for molecular separation and catalytic processing. Analcime willsorb ammonia while excluding larger molecules whereas zeolite omega willsorb perfluorotributyl amine [C₄ F₉)₃ N]while excluding any moleculehaving a diameter greater than about 10.0 Angstroms. All of the otherapproximately 150 zeolites now known have pore sizes falling within therange between 2.6 and 10.0 Angstroms.

In addition to their use as drying agents and selective sorbents,zeolites are widely used as components of chemical conversion catalysts.As found in nature or as synthesized, zeolites are typically inactivebecause they lack acid sites. In general, acid sites are created bysubjecting the zeolite to an ion exchange with ammonium ions followed bysome type of thermal treatment which creates acid sites by decomposingthe ammonium ions into gaseous ammonia and protons. Activated zeoliteshave been used in many types of chemical conversion processes with thesmaller pore zeolites being used to selectively sorb and crack normaland moderately branched chain paraffins.

Because of the unique properties of zeolitic molecular sieves, therehave been many attempts at synthesizing new molecular sieves by eithersubstituting an element for the aluminum or silicon present in zeoliticmolecular sieves or adding another element in addition to the aluminumand silicon. The term "zeolitic" as used herein refers to molecularsieves whose frameworks are formed of substantially only silica andalumina tetrahedra. One such class of new molecular sieves that has beencreated is that in which all the framework aluminum has been replaced bygallium. Specifically, it has been reported in the literature thatgalliosilicate molecular sieves having the faujasite structure, thepentasil structure and the mordenite structure have been synthesized.The synthesis of a galliosilicate analogue of Theta-1 zeolite has alsobeen reported. There has, however, been no reported instance of agalliosilicate with the erionite-type structure having been synthesized.

Accordingly, it is one of the objects of the present invention toprovide a crystalline, galliosilicate molecular sieve with theerionite-type structure, and a method for preparing such a molecularsieve, which may be useful in many types of chemical conversionprocesses, particularly hydrocarbon conversion processes. This and otherobjects of the invention will become more apparent in view of thefollowing description of the invention.

SUMMARY OF THE INVENTION

In accordance with the invention it has now been found that acrystalline, galliosilicate molecular sieve comprising silicon, galliumand oxygen and having the erionite-type crystal structure can besynthesized by mixing a source of gallia, a source of silica, a sourceof one alkali metal, a source of a different alkali metal, a templatingagent and water to form a hydrogel in which the components have thefollowing mole ratios:

SiO₂ /Ga₂ O₃ =8 to 30

(M₂ O+N₂ O)/Ga₂ O₃ =1 to 15

H₂ O/Ga₂ O₃ =80 to 1000

Q₂ O/Ga₂ O₃ =0.1 to 10

where M is an alkali metal, N is an alkali metal other than M and Q is acation derived from the templating agent. After the above-describedhydrogel is formed, it is crystallized to form the synthetic,crystalline, galliosilicate molecular sieve of the invention. Thismolecular sieve typically has the composition, expressed in terms ofoxide mole ratios in the anhydrous state, of

    Ga.sub.2 O.sub.3 :xSiO.sub.2 :yM.sub.2 O:zN.sub.2 O:tQ.sub.2 O

where x equals 5.5 to 30, y equals 0.1 to 0.9, z equals 0.1 to 0.9, tequals 0.1 to 0.6, and z+y+t equals about 1.0. The X-ray powderdiffraction pattern of the molecular sieve contains at least thed-spacings set forth in Table 1 below, which d-spacings arecharacteristic of a zeolite with the erionite-type structure.

                  TABLE 1                                                         ______________________________________                                        Interplanar                                                                   d-spacings    Relative Intensity                                              (Angstroms)   (100 × I/I.sub.o)                                         ______________________________________                                        11.52 ± 0.50                                                                             80-100                                                          9.17 ± 0.30                                                                              2-20                                                            6.64 ± 0.20                                                                              30-60                                                           5.36 ± 0.20                                                                              2-20                                                            4.98 ± 0.15                                                                              2-20                                                            4.40 ± 0.15                                                                              30-60                                                           4.20 ± 0.15                                                                              2-25                                                            3.77 ± 0.15                                                                              30-100                                                          3.61 ± 0.10                                                                              30-80                                                           2.86 ± 0.10                                                                              30-90                                                           ______________________________________                                    

In a preferred galliosilicate molecular sieve, M is sodium, N ispotassium, and Q is a quaternary ammonium cation, most preferably acholine cation.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 in the drawing shows the X-ray powder diffraction pattern of anatural zeolite with the erionite structure; and

FIG. 2 depicts the X-ray powder diffraction pattern of the molecularsieve of the invention, i.e., a crystalline galliosilicate with theerionite-type structure.

DETAILED DESCRIPTION OF THE INVENTION

The crystalline, galliosilicate molecular sieve of the invention isprepared by crystallizing a hydrogel formed by mixing a source ofgallia, a source of silica, a source of two different alkali metals anda templating agent with water under conditions such that the variouscomponents react to form the desired hydrogel. Since a source of aluminais not used in forming the hydrogel, the only alumina present in thecrystallized galliosilicate will be alumina impurities in the othersource materials. Thus, the galliosilicate molecular sieve of theinvention will normally contain less than about 0.1 weight percentalumina, preferably less than 0.05 weight percent, and will usually besubstantially free of both alumina and aluminum.

The silica used in forming the hydrogel may be in the form of sodiumsilicate, silica hydrosols, silica gels, silica salts and reactiveamorphous solid silicas. The source of the silica can be in either theliquid or solid state. Examples of reactive, amorphous solid silicasthat may be used include fumed silicas, chemically precipitated silicas,and precipitated silica sols usually having a particle size of less than1 micron in diameter. The preferable sources of silica are sodiumsilicates (water glass) and aqueous colloidal dispersions of silicaparticles.

The source of alkali metals used in forming the hydrogel may be analkali metal salt or hydroxide. Although any combination of twodifferent alkali metal sources may be utilized, it is preferable that asource of sodium and a source of potassium be employed. It is possiblefor the source of the alkali metal to also be the source of galliautilized to form the hydrogel. Alkali metal gallates are examples ofmaterials which serve as a source of both an alkali metal and gallia.

The gallia used to produce the hydrogel from which the galliosilicatemolecular sieve of the invention is crystallized may be in the form ofgallium oxide, gallium hydroxide, an alkali metal gallate or aninorganic gallium salt, such as gallium nitrate, gallium sulfate, andgallium acetate. As mentioned above, the source of the gallia may alsobe the source of the alkali metals required to form the hydrogel. Infact, a preferred source of gallia is prepared by dissolving galliumoxide in an aqueous solution of sodium and potassium hydroxide to formpotassium gallate and sodium gallate which are then used as componentsto form the hydrogel.

The templating agent used to form the hydrogel is normally any componentwhich directs crystallization of the hydrogel toward the erionite-typestructure. Typically, the templating agent is either an amine or certaintypes of quaternary ammonium compounds. Examples of amines useful as thetemplating agent include ethylene diamine, diethyl triamine, triethylenetetraamine, and alkanolamines. The preferred templating agents includequaternary ammonium compounds selected from the group consisting ofcholine chloride, benzyltrimethyl ammonium chloride or hydroxide,benzyltriethyl ammonium chloride or hydroxide and derivatives of1,4-diazabicyclo (2,2,2) octane. The most preferred templating agentsfor use in making the crystalline galliosilicate of the invention arecholine salts such as choline chloride and the like.

The hydrogel from which the galliosilicate molecular sieve of theinvention is crystallized is normally prepared by first dissolving thesource of gallia in a clear solution containing a mixture of two alkalimetal hydroxides, preferably potassium and sodium hydroxide. Theresulting solution is then mixed with a templating agent and a source ofsilica to form the gel which is then vigorously stirred. A sufficientamount of the gallia source, the silica source, the sources of alkalimetals, the templating agent and water is used so that the resultanthydrogel contains the following oxide mole ratios of components:

SiO₂ /Ga₂ O₃ =8 to 30, preferably 10 to 15

(M₂ O+N₂ O)/Ga₂ O₃ =1 to 15, preferably 2 to 5

H₂ O/Ga₂ O₃ =80 to 1000, preferably 100 to 400

Q₂ O/Ga₂ O₃ =0.1 to 10, preferably 0.5 to 4.0

where M is an alkali metal, preferably sodium, N is another alkalimetal, preferably potassium, and Q is a cation derived from thetemplating agent, preferably a choline cation, a benzyltrimethylammonium cation, a benzyltriethyl ammonium cation or a cation derivedfrom 1,4-diazabicyclo (2,2,2) octane. In order to maximize the yield ofcrystals having the erionite-type structure during crystallization of ahydrogel in which M is sodium and N is potassium, it is normallypreferred that the concentration of the sodium and potassium in thehydrogel be such that the mole ratio of K₂ O-to-Na₂ O is below about1.0. This is especially true when Q is a choline cation, abenzyltrimethyl ammonium cation, a benzyltriethyl ammonium cation or acation derived from 1,4-diazobicyclo (2,2,2) octane.

After all of the components of the hydrogel have been combined together,the hydrogel is vigorously stirred at atmospheric pressure and at atemperature between about 20° C. and about 150° C., preferably at aboutroom temperature, for from about 1 hour to about 2 days, preferablybetween about 1 hour and about 10 hours. After stirring, the hydrogel iscrystallized by heating, with or without stirring, for between about 2days and 10 days at temperatures in the range between about 70° C. and250° C., preferably between about 90° C. and 175° C. The temperature isnormally controlled within the above ranges to avoid the formation ofphase impurities. After the hydrogel has been crystallized, theresulting slurry is passed to a filter, centrifuge or other separationdevice to remove the excess reactants or mother liquor from thecrystallized molecular sieve. The crystals are then washed with waterand dried at a temperature between about 50° C. and about 200° C. toremove surface water.

The dried crystals produced as described above comprise the molecularsieve of the invention and will normally have the following compositionexpressed in terms of oxide mole ratios in the anhydrous state:

    Ga.sub.2 O.sub.3 :xSiO.sub.2 :yM.sub.2 O:zN.sub.2 O:tQ.sub.2 O (1)

where M is an alkali metal, preferably sodium, N is an alkali metalother than M, preferably potassium, Q is a cation derived from thetemplating agent used in synthesizing the molecular sieve of theinvention, x equals 5.5 to 30, preferably 6 to 15, y equals 0.1 to 0.9,z equals 0.1 to 0.9, t equals 0.1 to 0.6 and the sum of y, z, and tequals approximately 1.0. The X-ray powder diffraction pattern of thecrystallized molecular sieve of the invention will typically contain atleast the d-spacings set forth in Table 1, preferably the d-spacings setforth in Table 2 below.

                  TABLE 2                                                         ______________________________________                                        Bragg Angle  Interplanar                                                      2-Theta      d-spacings Relative Intensity                                    (Degrees)    (Angstroms)                                                                              (100 × I/I.sub.o)                               ______________________________________                                        7.5-7.9      11.78-11.18                                                                               80-100                                               9.4-9.9      9.40-8.93   2-20                                                 11.4-11.8    7.5-7.49   15-30                                                 13.1-13.5    6.75-6.55  30-60                                                 13.7-14.2    6.46-6.23   5-25                                                 15.2-15.6    5.82-5.67  15-40                                                 16.3-16.7    5.43-5.30   2-20                                                 17.6-18.0    5.03-4.92   2-20                                                 19.1-19.6    4.64-4.52  15-60                                                 20.2-20.6    4.39-4.31  30-60                                                 21.1-21.5    4.21-4.13   2-25                                                 23.0-23.5    3.86-3.78  30-60                                                 23.4-23.8    3.80-3.73   30-100                                               24.4-24.9    3.64-3.57  30-80                                                 26.7-27.2    3.33-3.27  15-45                                                 28.1-28.5    3.17-3.13  10-35                                                 31.0-31.4    2.88-2.85  30-90                                                 31.6-32.0    2.83-2.79   5-30                                                 33.1-33.5    2.70-2.67   5-30                                                 35.6-36.0    2.52-2.49   5-25                                                 ______________________________________                                    

The X-ray powder diffraction data set forth in Tables 1 and 2 arecharacteristic of a molecular sieve having the erionite-type structure.For comparison purposes, the X-ray powder diffraction pattern of anatural erionite found in or around the area of Rome, Oregon is shown inFIG. 1, and the corresponding X-ray powder diffraction data are setforth in Table 3. Natural erionite from Rome, Oregon has been describedin a paper by F. A. Mumpton and W. C. Ormsby entitled "Morphology ofZeolites in Sedimentary Rocks by Scanning Electron Microscopy,"appearing beginning at page 113 in the book entitled Natural Zeolites,Occurrence, Properties, Use," edited by L. B. Sound and F. A. Mumptonand published by Pergamon Press in 1978. The disclosure of this book ishereby incorporated by reference in its entirety.

                  TABLE 3                                                         ______________________________________                                        X-Ray Diffraction Data for a Natural Zeolite                                  with the Erionite Structure                                                   Bragg Angle  Interplanar                                                      2-Theta      d-spacings Relative Intensity                                    (Degrees)    (Angstroms)                                                                              (100 × I/I.sub.o)                               ______________________________________                                         7.715       11.4505    100.0                                                  9.676       9.1336     6.8                                                   11.719       7.5452     11.3                                                  13.382       6.6111     51.6                                                  14.052       6.2973     6.7                                                   15.472       5.7227     13.8                                                  16.556       5.3502     16.8                                                  19.425       4.5659     10.0                                                  20.519       4.3249     43.3                                                  21.348       4.1589     20.1                                                  23.311       3.8128     28.1                                                  23.685       3.7534     54.7                                                  24.877       3.5763     31.2                                                  26.657       3.3413     10.8                                                  26.975       3.3027     18.0                                                  28.114       3.1715     7.4                                                   28.338       3.1489     15.2                                                  30.569       2.9221     7.3                                                   31.260       2.8590     36.3                                                  31.433       2.8437     41.4                                                  31.797       2.8120     25.0                                                  33.468       2.6753     12.0                                                  35.954       2.4958     10.2                                                  36.154       2.4824     10.8                                                  39.284       2.2916     2.7                                                   40.936       2.2029     6.5                                                   43.494       2.0790     3.0                                                   45.720       1.9828     3.7                                                   46.345       1.9575     3.1                                                   ______________________________________                                    

The X-ray powder diffraction data set forth in Tables 1 and 2 for thecrystalline galliosilicate of the invention are based on data obtainedusing a Siemens D-500 X-ray diffractometer with a graphite-crystalmonochromatized Cu-K alpha radiation. The peak heights I, and theirposition as a function of 2-theta, where theta is the Bragg angle, wereread from the diffractometer output. From this output the relativeintensities, 100×I/I_(o), where I_(o) is the intensity of the strongestpeak, were read. The interplanar spacings, d, in Angstroms correspondingto the recorded peaks were then calculated in accordance with standardprocedures. It will be understood that the peak heights and d-spacingsassociated with the X-ray powder diffraction pattern of thegalliosilicate molecular sieve of the invention may vary somewhatdepending on heat treatment, unit cell composition, crystal size, andwhether the molecular sieve has been exchanged with hydrogen ions ormetal cations.

The water content of the crystalline, galliosilicate molecular sieve ofthe invention will depend on the method used for drying the particlesformed upon crystallization. The amount of cations derived from thetemplating agent present in the dried molecular sieve will depend uponthe silica-to-gallia mole ratio and the alkali metal content of thegalliosilicate crystals. In general, the moles t of Q₂ O present, asshown in formula (1) above, will equal about 1.0 minus the sum of themoles of the two different alkali metal oxides present, z+y.

After the synthesized galliosilicate crystals have been washed anddried, they are typically treated in order to render them active foracid catalyzed reactions. This procedure normally comprises calciningthe washed and dried crystals in air at a temperature between about 400°C. and about 700° C., preferably between about 500° C. and about 600°C., for between about 5 hours and about 15 hours to decompose thecations derived from the templating agent into gaseous products. Afterthis calcination, the galliosilicate molecular sieve is again treated,normally by ion exchange with ammonium cations, to reduce its alkalimetal content to below about 2.0 weight percent, preferably below about0.5 weight percent and most preferably below about 0.05 weight percent,calculated as the alkali metal oxide. When reducing the alkali metalcontent using an ammonium ion exchange technique, the molecular sieve istypically slurried for 1 to 5 hours at a temperature above ambienttemperature but less than about 100° C. in an aqueous solutioncontaining a dissolved ammonium salt, such as ammonium nitrate, ammoniumsulfate, ammonium chloride and the like. Ordinarily, to achieveextremely low levels of alkali metal cations, the ion exchange procedurewill be repeated at least twice, and occasionally several times. Afterthe ammonium exchange or other treatment to reduce alkali metal content,the molecular sieve is again calcined in air under conditions similar tothose used in the first calcination step. Calcination after an ammoniumexchange serves to decompose the ammonium cations into ammonia, which isdriven off during the calcination step, and thereby produce thecatalytically active hydrogen form of the galliosilicate molecularsieve.

The crystalline, galliosilicate molecular sieve of the invention may beused as a catalyst for converting hydrocarbons and other organiccompounds into more valuable reaction products by acid catalyzedreactions, such as alkylation, transalkylation, dealkylation,isomerization, dehydrocyclization, dehydrogenation, hydrogenation,cracking, hydrocracking, dewaxing, hydrodewaxing, oligomerization,aromatization, alcohol conversion reactions, the conversion of syngas tomixtures of hydrocarbons and the like. In utilizing the galliosilicatesof the invention as a catalyst in conversion processes as describedabove, it will normally be combined with a porous, inorganic refractoryoxide component, or a precursor thereof, such as alumina, silica,titania, magnesia, zirconia, beryllia, silica-alumina, silica-magnesia,silica-titania, a dispersion of silica-alumina in gamma alumina, a claysuch as kaolin, hectorite, sepiolite and attapulgite, combinations ofthe above and the like. The preferred porous, inorganic refractory oxidecomponent will depend upon the particular conversion process involvedand will be known to those skilled in the art. Examples of precursorsthat may be used include peptized alumina, alumina gel hydrated alumina,silica-alumina, hydrogels, Ziegler-derived aluminas and silica sols. Theexact amounts of crystalline galliosilicate and porous, inorganicrefractory oxide used in the catalyst of the invention will again dependupon the particular conversion process in which the catalyst is to beused.

It will be understood that although the primary use of the catalyst ofthe invention will be in hydrocarbon conversion processes to converthydrocarbon feedstocks into desirable reaction products, the catalystcan also be used to convert feedstocks or organic compounds other thanhydrocarbons into desired reaction products. For example, the catalystof the invention can be used to convert alcohols into transportationfuels and to convert gaseous mixtures of carbon monoxide and hydrogeninto hydrocarbons. As used herein "hydrocarbon" refers to any compoundwhich comprises hydrogen and carbon and "hydrocarbon feedstock" refersto any charge stock which contains a mixture of hydrocarbon compoundsand comprises greater than about 70 weight percent carbon and hydrogen,preferably greater than about 80 weight percent, calculated as theelements.

Depending on the particular type of conversion process in which thecatalyst of the invention is to be used, it may be desirable that thecatalyst also contain a metal promoter or combination of metal promotersselected from Group IB, Group IIB, Group IIIA, Group IVA, Group VA,Group VIB, Group VIIB or Group VIII of the Periodic Table of elements.As used herein "Periodic Table of Elements" refers to the version foundin the inside front cover of the "Handbook of Chemistry and Physics,"65the Edition, published in 1984 by the Chemical Rubber Company,Cleveland, Ohio. Specific metal components which may be used aspromoters include components of copper, silver, zinc, aluminum, gallium,indium, thallium, lead, tin, antimony, bismuth, chromium, molybdenum,tungsten, manganese, iron, cobalt, nickel, ruthenium, rhodium,palladium, iridium, platinum, rhenium, thorium and the rare earths.These metal promoters may be ion exchanged into the crystallinegalliosilicate itself, they may be incorporated into the mixture of thecrystalline galliosilicate and the porous, inorganic refractory oxide,or they may be added by impregnation after the catalyst particles havebeen formed.

The catalyst of the invention is normally prepared by mulling thecrystalline galliosilicate molecular sieve in powder form with theporous, inorganic refractory oxide component. If desired, a binder suchas peptized Catapal alumina may be incorporated into the mullingmixture, as also may be one or more active promoter metal precursors.After mulling, the mixture is extruded through a die having openings ofa cross sectional size and shape desired in the final catalystparticles. For example, the die may have circular openings to producecylindrical extrudates, openings in the shape of three-leaf clovers soas to produce an extrudate material similar to that shown in FIGS. 8 and8A of U.S. Pat. No. 4,028,227, the disclosure of which is herebyincorporated by reference in its entirety, or openings in the shape offour-leaf clovers. Among preferred shapes for the die openings are thosethat result in particles having surface-to-volume ratios greater thanabout 100 reciprocal inches. If the die opening is not circular inshape, it is normally desirable that the opening be in a shape such thatthe surface-to-volume ratio of the extruded particles is greater thanthat of a cylinder. After extrusion, the extruded catalyst particles arebroken into lengths of from 1/16 to 1/2 inch and calcined in air at atemperature of at least 750° F., usually between about 800° F. and about1200° F., and preferably in the range between about 900° F. and 1050° F.

As mentioned previously, metal promoter components may be mulled, eitheras a solid or liquid, with the galliosilicate of the invention and theporous, inorganic refractory oxide component to form the catalystextrudates prior to the calcination step. Alternatively, the metalpromoter component or components may be added to the catalyst byimpregnation after the calcination step. The metal promoter component orcomponents may be impregnated into the calcined extrudates from a liquidsolution containing the desired metal promoter component or componentsin dissolved form. In some cases, it may be desirable to ion exchangethe calcined extrudates with ammonium ions prior to adding the metalpromoter component or components. After the calcined extrudates havebeen impregnated with the solution containing the metal promotercomponent or components, the particles are dried and calcined in the airat a temperature normally ranging between about 800° F. and about 1100°F. to produce the finished catalyst particles.

In addition to the crystalline, galliosilicate molecular sieve of theinvention, the catalyst of the invention may also contain othermolecular sieves such as aluminosilicates, borosilicates,aluminophosphates, silicoaluminophosphates, naturally occurringzeolites, pillared clays and delaminated clays. Suitablealuminosilicates for combining with the crystalline galliosilicate ofthe invention include Y zeolites, ultrastable Y zeolites, X zeolites,zeolite beta, zeolite L, faujasite and zeolite omega. The actualmolecular sieve used in combination with the crystalline galliosilicatewill depend upon the particular conversion process in which the catalystof the invention is to be used. The molecular sieve of choice isnormally incorporated into the catalyst by mixing the molecular sievewith the crystalline galliosilicate and porous, inorganic refractoryoxide prior to mulling and extrusion.

It is typically preferred to use catalysts containing the crystallinegalliosilicate molecular sieve of the invention in hydroconversionprocesses such as hydrocracking, isomerization and hydrodewaxing. Whenused in such processes, the catalyst will normally contain hydrogenationcomponents comprising metals selected from Group VIII and/or Group VIBof the Periodic Table of Elements. These hydrogenation metal componentsare incorporated into the catalyst extrudates either prior to or afterextrusion. Examples of Group VIII and Group VIB metal components thatmay be used include nickel, cobalt, tungsten, molybdenum, palladium andplatinum components. In some cases, it may be desirable that thecatalyst contain at least one Group VIII metal component and at leastone Group VIB metal component. When this is the case, the preferredcombination is a nickel and/or cobalt component with a molybdenum and/ortungsten component.

If the hydrogenation metal component consists essentially of a noblemetal such as platinum or palladium, it is generally desired that thefinished catalyst particles contain between about 0.05 and about 10weight percent of the hydrogenation metal component, preferably betweenabout 0.10 weight percent and about 3.0 weight percent, calculated asthe metal. If on the other hand, the hydrogenation metal componentconsists essentially of one or more non-noble metals, such as nickel ornickel and tungsten, it is normally desired that the finished catalystparticles contain between about 1.0 and about 40 weight percent of thehydrogenation metal components, preferably between about 3 weightpercent and about 30 weight percent, calculated as the metal oxide.

Feedstocks that may be subjected to hydroconversion processes using thecatalyst of the invention include mineral oils, synthetic oils, such asshale oil, oil derived from tar sands and coal liquids, and the like.Examples of appropriate feedstocks for hydroconversion processes includestraight run gas oils, vacuum gas oils and catalytic crackerdistillates. Preferred hydroconversion feedstocks include gas oils andother hydrocarbon fractions having at least about 50 weight percent oftheir components boiling above about 700° F.

In general, the temperature at which the hydroconversion process takesplace is between about 450° F. and about 850° F., preferably betweenabout 600° F. and about 800° F. The pressure will normally range betweenabout 750 and about 3500 p.s.i.g., preferably between about 1000 andabout 3000 p.s.i.g. The liquid hourly space velocity (LHSV) is typicallybetween about 0.3 and about 5.0, preferably between about 0.5 and about3.0. The ratio of hydrogen gas to feedstock utilized will usually rangebetween about 1000 and about 10,000 scf/bbl, preferably between about2000 and about 8000 scf/bbl as measured at 60° F. and one atmosphere.

The pore size of the crystalline, galliosilicate molecular sieve of theinvention will normally vary between about 4.0 and about 6.0 Angstromsbecause of stacking faults typically associated with the erionite-typestructure. Such a range of pore sizes makes the crystallinegalliosilicate of the invention particularly suited for use as acomponent of a catalyst employed in dewaxing or hydrodewaxing processes.Dewaxing and hydrodewaxing differ from hydrocracking in that theseprocesses involve the selective cracking of molecules and do notsignificantly change the boiling point range of the feedstock becauseessentially only the straight and slightly branched chain paraffinmolecules in the feedstock are cracked while essentially all the highlybranched chain paraffins, aromatic and cyclic molecules in the feedstockremain unchanged. Hydrocracking, on the other hand, involves theindiscriminate or nonselective cracking of molecules in the presence ofadded hydrogen and always results in a significant alteration of theboiling point range of the feedstock because a substantial proportion ofall types of molecules comprising the feedstock are converted into lowerboiling components. Hydrodewaxing differs from dewaxing in that theformer is carried out in the presence of added hydrogen while the latteris not.

The nature and objects of the invention are further illustrated by thefollowing examples, which are provided for illustrative purposes onlyand not to limit the invention as defined by claims. The examplesdemonstrate several methods of synthesizing a crystalline galliosilicatewith the erionite-type structure.

EXAMPLE 1

An aqueous solution of potassium hydroxide and sodium hydroxide isprepared by dissolving commercial grade potassium hydroxide and sodiumhydroxide crystals in distilled water. Gallium oxide is then added tothe solution and the resultant mixture is vigorously stirred underboiling conditions until the gallium oxide is completely dissolved.Choline chloride is then added as the templating agent to the basicsolution of gallium oxide and the mixture is stirred for an additional30 minutes. After stirring, Ludox HS-40, a colloidal silica solmanufactured and sold by the DuPont Chemical Company, is added dropwiseto the stirred mixture to form a hydrogel having the followingcomposition expressed in terms of oxide mole ratios:

Ga₂ O₃ :12 SiO₂ :2.4 Na₂ O:1.3 K₂ O:4.0 [(CH₃)₃ NCH₂ CH₂ OH]₂ O:250 H₂ O

The resultant hydrogel is stirred at room temperature for 10 hours andthen heated at about 125° C. in an autoclave for about 7 days. Thegalliosilicate crystals formed have the following composition expressedin terms of oxide mole ratios in the anhydrous state:

Ga₂ O₃ :6.54 SiO₂ :0.19 Na₂ O:0.37 K₂ O:0.51 [(CH₃)₃ NCH₂ CH₂ OH]₂ O

An X-ray diffractogram of the crystals is obtained using a Siemens D-500X-ray diffractometer with graphite-crystal monochromatized Cu-K alpharadiation. The resultant X-ray diffraction pattern is shown in FIG. 2and the corresponding X-ray diffraction data including the calculatedd-spacings are set forth in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        X-Ray Diffraction Data for the                                                Crystalline Galliosilicate of Example 1                                       Bragg Angle  Interplanar                                                      2-Theta      d-spacings Relative Intensity                                    (Degrees)    (Angstroms)                                                                              (100 × I/I.sub.o)                               ______________________________________                                         7.671       11.5149    100.0                                                  9.636       9.1710     9.9                                                   11.632       7.6018     20.1                                                  13.353       6.6254     51.6                                                  13.965       6.3363     8.1                                                   15.442       5.7336     32.4                                                  16.525       5.3602     8.4                                                   17.783       4.9838     8.1                                                   19.387       4.5749     38.3                                                  20.488       4.3314     45.4                                                  21.342       4.1600     10.0                                                  23.319       3.8116     43.2                                                  23.637       3.7609     60.8                                                  24.722       3.5983     58.7                                                  26.985       3.3015     32.1                                                  28.198       3.1662     25.6                                                  30.493       2.9292     6.3                                                   31.317       2.8540     56.5                                                  31.790       2.8125     12.2                                                  33.443       2.6773     13.2                                                  35.520       2.5253     6.7                                                   35.972       2.4946     15.6                                                  37.541       2.3939     3.0                                                   39.400       2.2851     8.7                                                   42.711       2.1153     3.3                                                   42.822       2.1101     3.0                                                   ______________________________________                                    

The X-ray powder diffraction pattern set in FIG. 2 is substantiallysimilar to that set forth in FIG. 1 for a natural zeolite with theerionite structure. Thus, it is concluded that the crystallinegalliosilicate synthesized in Example 1 has the erionite-type structure.The d-spacing values for the synthesized galliosilicate set forth inTable 4 are higher than the corresponding values in Table 3 for thezeolite with the erionite-type structure. These increases in d-spacingvalues are consistent with a larger unit cell size for thegalliosilicate as shown in Table 5 below. This larger unit cell size isattributed to the isomorphous substitution of gallium, which has alarger ionic radius than aluminum, for aluminum in the erionitestructure. Differences in the relative intensities set forth in Tables 3and 4 result mainly from the different unit cell composition and crystalsize of the two molecular sieves.

                  TABLE 5                                                         ______________________________________                                        Unit Cell Parameters                                                                          a.sub.o    c.sub.o                                            Molecular Sieve (Angstroms)                                                                              (Angstroms)                                        ______________________________________                                        Natural Erionite                                                                              13.212     15.089                                             Synthetic Ga-Erionite                                                                         13.228     15.200                                             ______________________________________                                    

The crystals of the galliosilicate formed in the autoclave are subjectedto calcination in flowing air at a temperature of 600° C. to decomposethe choline cations. The resultant crystals are then ion exchanged withammonium cations by slurrying the crystals in a 3 molar solution ofammonium nitrate. The ammonium-exchanged galliosilicate crystals arethen calcined at 600° C. for 10 hours. The resultant crystals have a BETsurface area of about 410 m² /gram and retain about 100 percent of theiroriginal crystallinity.

EXAMPLE 2

A hydrogel is prepared as described in Example 1 except that theresultant gel has the following composition expressed in terms of oxidemole ratios:

Ga₂ O₃ :14 SiO₂ 2.4 Na₂ O:1.3 K₂ O:4.0 [(CH₃)₃ NCH₂ CH₂ OH]₂ O:250 H₂ O

The resultant hydrogel is stirred at room temperature for 10 hours andthen heated at about 125° C. in an autoclave to form crystals. An X-raydiffractogram of the resultant crystals is obtained as described inExample 1. The resultant X-ray diffraction pattern is essentially thesame as that set forth in FIG. 2, which diffraction pattern was obtainedusing the crystals formed in Example 1. The X-ray diffraction data isalso similar to that set forth in Table 4 for the crystals formed inExample 1. Thus, it is concluded that the crystals are that of agalliosilicate having the erionite-type structure.

The crystals are calcined in flowing air at 550° C. for 10 hours toremove the choline cations. The resultant crystals have a BET surfacearea of 424 m² /gram and the composition, expressed in terms of oxidemole ratios, shown below.

Ga₂ O₃ :7.46 SiO₂ :0.11 Na₂ O:0.31 K₂ O

EXAMPLE 3

A hydrogel is prepared as described in Example 1 except thatbenzyltrimethyl ammonium hydroxide is used as the templating agent inplace of choline chloride. The benzyltrimethyl ammonium hydroxide is inthe form of a 40 weight percent solution in methanol known as Sumquat2311, which is available from the Excel Specialty Chemical Company. Theresulting hydrogel has the following composition expressed in terms ofoxide mole ratios:

Ga₂ O₃ :24 SiO₂ 2.0 Na₂ O:1.5 K₂ O:4.0 (C₁₀ H₁₆ N)₂ O:400 H₂ O

The hydrogel is stirred at room temperature for 10 hours and then heatedat about 170° C. for about 7 days to form crystals. An X-raydiffractogram of the crystals is obtained as described in Example 1. Theresultant X-ray diffraction pattern is essentially the same as that setforth in FIG. 2, which diffraction pattern was obtained during thecrystals formed in Example 1. The X-ray diffraction data is also similarto that set forth in Table 4 for the crystals formed in Example 1. Thus,it is concluded that the crystals are that of a galliosilicate havingthe erionite-type structure.

The crystals are calcined in flowing air at 550° C. for 10 hours toremove the benzyltrimethyl ammonium cations. The resultant crystals havethe composition, expressed in terms of oxide mole ratios, shown below.

Ga₂ O₃ :6.1 SiO₂ :0.5 K₂ O:0.13 Na₂ O

It will be apparent from the foregoing that the invention provides acrystalline, galliosilicate molecular sieve having the erionite-typestructure and methods for preparing such a sieve. Catalysts containingsuch a molecular sieve are useful in a variety of chemical conversionprocesses, particularly hydrocarbon conversion processes such asisomerization, hydrodewaxing and hydrocracking.

Although this invention has been primarily described in conjunction withexamples and by reference to embodiments thereof, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description.Accordingly, it is intended to embrace within the invention all suchalternatives, modifications and variations that fall within the spiritand scope of the appended claims.

I claim:
 1. A crystalline, galliosilicate molecular sieve substantiallyfree of aluminum having the following composition expressed in terms ofoxide mole ratios in the anhydrous state:Ga₂ O₃ :xSiO₂ :yM₂ O:zN₂ O:tQ₂Owhere M is an alkali metal, N is an alkali metal other than M, Q isselected from the group consisting of quaternary ammonium cations andprotonated amines, x equals 5.5 to 30, y equals 0.1 to 0.9, z equals 0.1to 0.9, t equals 0.1 to 0.6 and y+z+t equals about 1.0, said crystallinegalliosilicate molecular sieve having an X-ray powder diffractionpattern comprising the d-spacings set forth below:

    ______________________________________                                        Interplanar                                                                   d-spacings     Relative                                                       (Angstroms)    Intensity                                                      ______________________________________                                        11.52 ± 0.50                                                                               80-100                                                        9.17 ± 0.30  2-20                                                          6.64 ± 0.20 30-60                                                          5.36 ± 0.20  2-20                                                          4.98 ± 0.15  2-20                                                          4.40 ± 0.15 30-60                                                          4.20 ± 0.15  2-25                                                          3.77 ± 0.15  30-100                                                        3.61 ± 0.10 30-80                                                          2.86 ± 0.10 30-90                                                          ______________________________________                                    


2. A galliosilicate molecular sieve as defined by claim 1 wherein M issodium and N is potassium.
 3. A galliosilicate molecular sieve asdefined by claim 1 wherein Q comprises a quaternary ammonium cation. 4.A galliosilicate molecular sieve as defined by claim 3 wherein saidquaternary ammonium cation is selected from the group consisting ofcholine cations benzyltrimethyl ammonium cations, benzyltriethylammonium cations and 1,4-diazabicyclo (2,2,2) octane cations.
 5. Agalliosilicate molecular sieve as defined by claim 2 wherein Q comprisesa choline cation.
 6. A galliosilicate molecular sieve as defined byclaim 5 wherein x equals 6 to
 15. 7. A galliosilicate molecular sieve asdefined by claim 6 wherein said X-ray powder diffraction patterncomprises at least the d-spacings set forth below:

    ______________________________________                                        Interplanar                                                                   d-spacings     Relative                                                       (Angstroms)    Intensity                                                      ______________________________________                                        11.78- 11.18    80-100                                                        9.40-8.93       2-20                                                          7.75-7.49      15-30                                                          6.75-6.55      30-60                                                          6.46-6.23       5-25                                                          5.82-5.67      15-40                                                          5.43-5.30       2-20                                                          5.03-4.92       2-20                                                          4.64-4.52      15-60                                                          4.39-4.31      30-60                                                          4.21-4.13       2-25                                                          3.86-3.78      30-60                                                          3.80-3.73       30-100                                                        ______________________________________                                    


8. A crystalline, galliosilicate molecular sieve comprising silicon,gallium and oxygen, said molecular sieve substantially free of aluminumhaving an X-ray power diffraction pattern characteristic of the erionitestructure.
 9. A crystalline, galliosilicate molecular sieve as definedby claim 8 further comprising benzyltriethyl ammonium cations or1,4-diazabicyclo (2,2,2) octane cations.
 10. A galliosilcate molecularsieve as defined by claim 8 having the following composition expressedin terms of oxide mole ratios in the anhydrous state:GA₂ O₃ :xSiO₂ :yM₂O:zN₂ O:tQ₂ Owhere M is an alkali metal, N is an alkali metal other thanM, Q is selected from the group consisting of quaternary ammoniumcations and protonated amines, x equals 5.5 to 30, y equals 0.1 to 0.9,z equals 0.1 to 0.9, t equals 0.1 to 0.6 and y+z+t equals about 1.0. 11.A galliosilicate molecular sieve as defined by claim 8 furthercomprising sodium and potassium.
 12. A galliosilicate molecular sieve asdefined by claim 11 having the following composition expressed in termsof oxide mole ratios in the anhydrous state:Ga₂ O₃ :xSiO₂ :yNa₂ O:zK₂O:t[(CH₃)₃ NCH₂ CH₂ OH]₂ Owhere x equals 5.5 to 30, y equals 0.1 to 0.9,z equals 0.1 to 0.9, t equals 0.1 to 0.6, and y+z+t equals about 1.0.13. A galliosilicate molecular sieve as defined by claim 10 wherein M issodium and N is potassium.
 14. A galliosilicate molecular sieve asdefined by claim 10 wherein Q is a quaternary ammonium cation.
 15. Agalliosilicate molecular sieve as defined by claim 14 wherein saidquaternary ammonium cation is selected from the group consisting ofcholine cations, benzyltrimethyl ammonium cations, benzyltriethylammonium cations and 1,4-diazabicyclo (2,2,2) octane cations.
 16. Agalliosilicate molecular sieve as defined by claim 13 wherein Q is acholine cation.
 17. A crystalline, galliosilicate molecular sievesubstantially free of aluminum having the following compositionexpressed in terms of oxide mole ratios in the anhydrous state:Ga₂ O₃:xSiO₂ :yM₂ O:zN₂ O:tQ₂ Owhere M is an alkali metal, N is an alkalimetal other than M, Q is a quaternary ammonium cation, x equals 5.5 to30, y equals 0.1 to 0.9, z equals 0.1 to 0.9, t equals 0.1 to 0.6, andy+z+t equals about 1.0, said crystalline galliosilicate molecular sievehaving an X-ray powder diffraction pattern characteristic of theerionite structure.
 18. A galliosilicate molecular sieve as defined byclaim 17 wherein M is sodium, N is potassium and x equals 6 to
 15. 19. Agalliosilicate molecular sieve as defined by claim 18 wherein Q isselected from the group consisting of choline cations, benzyltrimethylammonium cations, benzyltriethyl ammonium cations and 1,4-diazabicyclo(2,2,2) octane cations.
 20. A process for preparing a crystalline,galliosilicate molecular sieve substantially free of aluminum whichcomprises:(a) mixing in the absence of an added source of alumina asource of gallia, a source of silica, a source of one alkali metal, asource of a different alkali metal, a templating agent and water to forma hydrogel substantially free of alumina having the following oxide moleratios of components: SiO₂ /Ga₂ O₃ =8 to 30 (M₂ O+N₂ O)/Ga₂ O₃ =1 to 15H₂ O/Ga₂ O₃ =80 to 1000 Q₂ O/Ga₂ O₃ =0.1 to 10 wherein M is an alkalimetal, N is an alkali metal other than M and Q is selected from thegroup consisting of quaternary ammonium cations and protonated amines;and (b) crystallizing said hydrogel to form crystals of saidgalliosilicate molecular sieve, said crystals having an X-ray powderdiffraction pattern comprising the d-spacings set forth below:

    ______________________________________                                        Interplanar                                                                   d-spacings     Relative                                                       (Angstroms)    Intensity                                                      ______________________________________                                        11.52 ± 0.50                                                                               80-100                                                        9.17 ± 0.30  2-20                                                          6.64 ± 0.20 30-60                                                          5.36 ± 0.20  2-20                                                          4.98 ± 0.15  2-20                                                          4.40 ± 0.15 30-60                                                          4.20 ± 0.15  2-25                                                          3.77 ± 0.15  30-100                                                        3.61 ± 0.10 30-80                                                          2.86 ± 0.10  30-90.                                                        ______________________________________                                    


21. A process as defined by claim 20 wherein Q is a benzyltriethylammonium cation or a 1,4-diazabicyclo (2,2,2) octane cation.
 22. Aprocess as defined by claim 20 wherein said X-ray powder diffractionpattern is characteristic of the erionite structure.
 23. A process asdefined by claim 20 wherein M is sodium and N is potassium.
 24. Aprocess as defined by claim 23 wherein Q comprises a quaternary ammoniumcation selected from the group consisting of choline cations,benzyltrimethyl ammonium cations, benzyltriethyl ammonium cations and1,4-diazabicyclo (2,2,2) octane cations.
 25. A process as defined byclaim 24 wherein said hydrogel has a mole ratio of K₂ O-to-Na₂ O of lessthan about 1.0.
 26. A process as defined by claim 25 wherein Q comprisescholine cations.
 27. A process as defined by claim 26 wherein saidhydrogel has the following oxide mole ratios of components:SiO₂ /Ga₂ O₃=10 to 15 (Na₂ O+K₂ O)/Ga₂ O₃ =2 to 5 H₂ O/Ga₂ O₃ =100 to 400 [(CH₃)₃NCH₂ CH₂ OH]₂ O/Ga₂ O₃ =0.5 to 4.0
 28. A process as defined by claim 27wherein said X-ray powder diffraction pattern comprises at least thed-spacings set forth below:

    ______________________________________                                        Interplanar                                                                   d-spacings     Relative                                                       (Angstroms)    Intensity                                                      ______________________________________                                        11.78-11.18     80-100                                                        9.40-8.93       2-20                                                          7.75-7.49      15-30                                                          6.75-6.55      30-60                                                          6.46-6.23       5-25                                                          5.82-5.67      15-40                                                          5.43-5.30       2-20                                                          5.03-4.92       2-20                                                          ______________________________________                                    


29. A process as defined by claim 22 wherein M is sodium and N ispotassium.
 30. A process as defined by claim 29 wherein Q comprises aquaternary ammonium cation selected from the group consisting of cholinecations, benzyltrimethyl ammonium cations, benzyltriethyl ammoniumcations and 1,4-diazabicyclo (2,2,2) octane cations.
 31. A process asdefined by claim 30 wherein said hydrogel has a mole ratio of K₂O-to-Na₂ O of less than about 1.0.
 32. A process as defined by claim 31wherein Q is a choline cation.
 33. A process as defined by claim 32wherein said hydrogel has the following oxide mole ratios ofcomponents:SIO₂ /Ga₂ O₃ =10 to 15 (Na₂ O+K₂ O)/Ga₂ O₃ =2 to 5 H₂ O/Ga₂O₃ =100 to 400 [(CH₃)₃ NCH₂ CH₂ OH]₂ O/Ga₂ O₃ =0.5 to 4.0.